1997 Toyota Camry Oil leaks when starts the engine

I have this problem for a long time, I had changed the valve cover gasket, the oil pan gasket, but the oil still leaks somewhere over the top of the oil pan, on the left front side of the engine. I thought that was power steering fluid at first, but it was not. The leaking fluid is yellow color, means oil. It is not dripping off when I park, but just drips down when I start the car for 5 minutes. The amount leaks at a time approximates a water bottle's cap. Please help.